Not long after their teams were dispatched from the 2012-13 playoffs, two long-time NHL coaches were relieved of their jobs. Despite five straight Northwest Division titles, two President's Trophies, and a Stanley Cup Finals appearance, Vancouver Canucks boss Alain Vigneault was let go after seven seasons, with the team and fans calling for a change in direction after two first-round playoff exits. Similarly, over in the Eastern Conference, the New York Rangers brought John Tortorella's four-season tenure to an end. Despite a record of 171-115-29 in Manhattan, Torts' brusque style alienated many on the team and in the local media, and his conservative, defensive approach was viewed as a poor fit for a young, talented roster.

Given their career accomplishments, few expected either coach to remain unemployed for long. Still, no one expected the odd twist that came in late June, when Vigneault was hired as the new boss of the Rangers, and Tortorella took over in Vancouver just days later. As someone who's wondered about the impact of head coaches on team performance, the swap of coaches represents an opportunity for an interesting natural experiment. How has switching from Vigneault to Tortorella been reflected in the Canucks' performance, and how has the reverse affected the Rangers?

Using data from Extra Skater, I compiled game-level advanced statistics from all 48 games of the Canucks' and Rangers' 2012-13 seasons, and the first 48 games of their 2013-14 seasons (completed as of January 15). Comparisons of the two teams in each of these seasons are depicted in the table below.

On the Vancouver side of things, the Canucks are just two points back of last season's 48-game pace, with an identical number of regulation losses. The team's shooting and save percentages are essentially unchanged. Under Tortorella, they've become more productive offensively, putting 2.5 more shots on goal and more Corsi attempts per 60 minutes at even strength, but it appears that Vancouver's opponents have the puck a bit more than they did last season: the Canucks give up almost 5 more Corsi attempts against per 60 than they did last season, even if their rate of shots on goal allowed hasn't changed (is this the famous Torts shot-blocking in action?).

While Vancouver's overall even-strength possession has declined slightly, score effects are still obvious at 48 games: the Canucks' Fenwick Close has improved under Tortorella. On special teams, Vancouver's power play is considerably improved, generating shots at a much higher rate than last season, even if the percentages haven't swung in their favor. Their penalty killing is largely unchanged, even if (despite their January 15 game vs. Anaheim) they're getting better PK goaltending.

In New York, on the other hand, the Rangers are five points behind last season's pace, though this is probably due to a drop in PDO from 1009 to 984 rather than any change implemented by Vigneault. The team's even-strength and close-game Fenwick percentages are down, however; the Rangers are allowing almost two more 5-on-5 shots on goal per 60 minutes than they were last season, so this isn't necessarily surprising. Much like Tortorella's Canucks, Vigneault's Rangers are creating more chances on the power play. Unlike the Canucks, however, this season's Rangers are allowing considerably fewer shots while shorthanded compared to 2012-13.

By way of summarizing, it appears as though the switch from Vigneault to Tortorella in British Columbia has boosted the Canucks' offensive productivity without measurably impacting their team defense. This is reflected in their special-teams performance: Vancouver generates a lot more changes on the power play than they did last season, and their play on the PK is largely unchanged. In New York, conversely, the arrival of Vigneault has seen a decline in the Rangers' possession numbers and an uptick in shots against, without much change in the rate of offense created. Where Vigneault has had the most positive impact, it appears, is on special teams: the Blue Shirts are a better team on both the power play and penalty kill this season.

Conclusion

It appears, then, that Vancouver is the winner of the "trade" after 48 games. These are both strong teams that I expect to see in the postseason. But the Canucks have had the stronger season playing in the far-tougher Pacific Division, their offensive production is improved without any noticeable drop in team defense, and their special teams, overall, are better as well. Vigneault's impact on New York's special teams has been undeniably positive, but NHL seasons are made and lost at even strength, and the drop in the Rangers' Fenwick Close and rise in the rate of shots they're allowing may come back to hurt them.